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Blockchain Certificate schemas extend those of Open Badges. As with Open Badges, we've provided both a JSON-LD context and JSON schema. The purpose of the JSON-LD context is to map types to Internationalized Resource Identifiers (IRIs), providing semantic context for data. The JSON Schema is used for syntactic validation.

This python package allows verification of a Blockchain Certificate against the JSON schemas as a convenience. This is not the same as verifying the contents of a certificate against what is stored on the blockchain. See the cert-verifier-js project.


The following is a Blockchain Certificate issued on the testnet Bitcoin network.

  "@context": [
  "type": "Assertion",
  "id": "urn:uuid:bbba8553-8ec1-445f-82c9-a57251dd731c",
  "badge": {
    "id": "urn:uuid:82a4c9f2-3588-457b-80ea-da695571b8fc",
    "type": "BadgeClass",
    "name": "Certificate of Accomplishment",
    "image": "data:image/png;base64,...",
    "description": "Lorem ipsum dolor sit amet, mei docendi concludaturque ad, cu nec partem graece. Est aperiam consetetur cu, expetenda moderatius neglegentur ei nam, suas dolor laudem eam an.",
    "criteria": {
      "narrative": "Nibh iriure ei nam, modo ridens neglegentur mel eu. At his cibo mucius."
    "issuer": {
      "id": "",
      "type": "Profile",
      "name": "University of Learning",
      "url": "",
      "email": "",
      "revocationList": "",
      "image": "data:image/png;..."
  "recipient": {
    "hashed": false,
    "identity": "",
    "type": "email"
  "recipientProfile": {
    "type": [
    "publicKey": "ecdsa-koblitz-pubkey:mtr98kany9G1XYNU74pRnfBQmaCg2FZLmc",
    "name": "Eularia Landroth"
  "issuedOn": "2017-06-29T14:58:57.461422+00:00",
  "verification": {
    "publicKey": "ecdsa-koblitz-pubkey:msBCHdwaQ7N2ypBYupkp6uNxtr9Pg76imj",
    "type": [
  "signature": {
    "type": [
    "targetHash": "637ec732fa4b7b56f4c15a6a12680519a17a9e9eade09f5b424a48eb0e6f5ad0",
    "merkleRoot": "f029b45bb1a7b1f0b970f6de35344b73cccd16177b4c037acbc2541c7fc27078",
    "anchors": [
        "sourceId": "d75b7a5bdb3d5244b753e6b84e987267cfa4ffa7a532a2ed49ad3848be1d82f8",
        "type": "BTCOpReturn"
    "proof": [
        "right": "11174e220fe74de907d1107e2a357e41434123f2948fc6b946fbfd7e3e3eecd1"

Open Badge Extensions

Details on Blockcerts extensions to Open Badges

Publishing package to pypi

Unit tests

This project uses tox to validate against several python environments.

  1. Ensure you have an python environment. Recommendations

  2. Run tests


Compile markdown from schema

Note that json-schema-to-markdown doesn't handle ref schemas well, so you will need to manually update any 'undefined' references.

scripts/generate_markdown.js builds the markdown-formatted schemas from json


Contact us at the Blockcerts community forum.